Metabolic phenomena related to ion transport in the urinary bladder of the turtle will be investigated. These are (1) respiratory activity of the turtle bladder with emphasis on the stoichiometry of sodium transport (O2 consumed to Na ion transported) in the face of varying electrical and osmotic work (2) specific metabolic pathways involved in ion transport (3) determination of the lipid composition of the turtle bladder and of the contribution of lipid to endogenous substrates. The stoichiometry of transport will be determined from simultaneous measurements of oxygen consumption with the oxygen electrode and Na ion fluxes by radioisotopes. Transport-related alterations in metabolism will be followed by carrying out multiple enzymic analyses of intermediates in the isolated mucosa of the turtle bladder after treatment with agents known to affect ion transport. Major classes of easily identified lipid will be analyzed for in both the mucosal (epithelial) and serosal (smooth muscle) portions of the bladder. Morphology of the tissue will be studied when appropriate. Findings in these areas will aid in the elucidation of the nature and control of the linkage between ion transport and energy-producing metabolic activity in the turtle bladder and, by extension, in other ion-transporting tissues.